<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style type="text/css">
        /* 块元素转行内元素 */
        
        div,
        p {
            display: inline;
        }
        /* 行内元素转块 */
        
        span {
            display: block;
            width: 400px;
            height: 400px;
            background-color: burlywood;
            text-align: center;
        }
    </style>
</head>

<body>
    <span>块元素</span>
    <span>行内元素</span>
</body>

</html>